Shock absorbing tow bar



Feb. 12, 1952 Q, HAM 2,585,768

SHOCK ABsoRBING Tow BAR- Filed June l2, 1950 2 SHEETS-SHEET l A mi F/'gJ2 James 0. Ham

IN VEN TOR.

BY WW Feb. 1.2, 1952 1 Q HAM 2,585,768

SHOCK ABSORBING TOW BAR Filed June l2, 1950 2 SI-IETS-SHEET 2 i 70 /00 vis James 0. Ham f INVENroR.

BY 5M@ Patented Feb. 12, 1952 UNITED STATES PATENT oFFlcE 2,585,768SHOCK ABSORBING TOW BAR James O. Ham, Goldsboro, N. C.

Application June 12, 1950, Serial No. 167,551

This invention relates to a shock-absorbing. tow bar and has for itsprimary objectto provide a detachable coupling between a towing vehicleand a towed vehicle which will effectively absorb shocks imparted toboth vehicles, particularly upon sudden stopping and quick starting ofthe towing vehicle.

Another important object of this invention is to provide ashock-absorbing tow bar which may be readily adjusted both horizontallyand vertically upon both the towing and towed vehicle.

Yet another object of this invention is to provide a shock-absorbing towbar construction which may be maintained in a horizontal position toprevent the towed car from running under and lifting up the towing car.

These, together with various ancillary objects and features of theinvention which will later become apparent as the following descriptionproceeds, are attained by the device, a preferred embodiment of whichhas been illustrated, by way of example only, in the accompanyingdrawings,

wherein:

Figure 1 is a top plan view of the device; Figure 2 is a sideelevational view of the device, the bumpers being shown in verticalsection;

Figure 3 is a sectional view taken substantially on the plane of sectionline 3-3 of Figure 1;

Figure 4 is a sectional viewtaken substantially on the plane of sectionline 4-4 of Figure 1;

Figure 5 is a sectional view taken substantiallyon the plane of sectionline 5--5 of Figure 1;

Figure 6 is a sectional view taken substantially on the plane of sectionline 6-6 of Figure 5; and

Figure 'l is a perspective View of one of the bumper attaching brackets.

Specific reference will now be made to the drawings. In the severalviews, in the accompanying drawings and in the following specification,similar reference characters indicate corresponding elements throughout.

The present tow bar construction comprises an elongated shaft in theform of a cylindrical tubular member I having an externally threaded endI2 upon which is received a nut I4 for a purpose later to appear. Theother end of the shaft I0 includes a closure I6 carrying alongitudinally extending apertured lug I8. A transversely extendingplate 20 is provided having a raised, substantially U-shaped portion 22centrally between its ends, the lug I8 extending into the portion 22 anda headed pivot pin 24 is made to extend through the portion 22 and theaperture in the lug I8 so that the shaft I0 is limited in its verticalmovement but is horizontally pivotal on the plate 20.

Claims. (Cl. 280--33.9)

A means for adjustably clamping the plate 20 upon the bumper 26 of thetowing vehicle is provided. This means comprises a pair of adjustableclamps 28, the complete construction of each of which is shown clearlyin Figures 5 to 7. Each bracket includes a U-shaped member 30 havingupper and lower leg portions 32 and 34 connected by a web portion 36. Alongitudinal slot 36 is provided in the web portion and appropriatelysecured between the legs 32 and 34 and to the web portion 36 on bothsides of the slot is a pair of vertically extending, spaced parallelplates 40 having horizontally aligned arcuate, vertically spacedrecesses 42. Extending between the plates 40-and through the slot 38 isa pair of hook members 44 which are adapted to hook over the bottom andtop edges of the bumper 26. The hook members are threaded at their endsto receive an arcuate bearing 46 selectively receivable in the alignedarcuate recesses 42, a closure nut 48 being received upon the threadedends of the hook members to retain the bearing 46 properly in place. Itwill thus be seen that each of the clamps 28 is vertically adjustable toaccommodate bumpers varying in width and each hook member is capable ofswivel action as shown clearly in dotted lines in Figure 5. verticallypivoted, as at 50, between 'the plates 40 is a lug 52 which isapertured, as

at 54, to receive a pin 56 selectively engageable in one ofthe pluralityof longitudinally spaced apertures 58 in the plate 20, the pins 56 beingthreaded at their ends to receive closure nuts 60.

Slidably received upon the shaft I0 adjacent its pivoted end is a collar62 having laterally extending lu'gs 64 for securing, as at 66, a pair ofrearwardly divergng bars 68 and 'I0 which are in turn secured at theirother ends adjustably to the bumper 'I2 of the towed vehicle by means ofclamps 28. Secured centrally to the shaft I0 is an annular flange orring 14 and interposed between the ring 'I4 and the slidable collar 62and wound about the shaft I8 is a coil spring 16 which is tensioned tonormally urge the slidable collar toward the plate 20. Secured by meansof an appropriate screw 'I8 to the upper end of the slidable collar 62is one end of a cylinder 86 in which is slidably received a piston rod82 that is secured vat its free end by means of a screw 84 to a nut 86adjustably threaded upon the threaded end l2 of the shaft I0.

A second collar 88 is slidably positioned upon the shaft I0 adjacent thethreaded end I2 thereof and interposed between the collar 88 and thering I4 on the shaft is a further coil spring 90 which normally urgesthe collar 88 toward the threaded free end of the shaft I0. The collar88 includes oppositely extending lugs 92 for securing, by means of thebolt and nut 94, transversely extending, vertically spaced bars 96 whichare apertured, as at 98, for a purpose later to appear. VA block isslidably received on the intermediate portion of each of the divergingbars 68 and 10 and is also received between the spaced, transverselyextending bars 96. A bolt and nut 102 is selectively received throughone of the apertures 98 and also extends through 'the block |00 and thebars 68 and 'lll so that, in effect, the slidable collar 88 may besecured ad'- justably, in a transverse direction 4:to 'the intermediateportions of the diverging bars 68 and 10. The longitudinally extendingbars NT4 are secured `between the two slidable `collars /62 and 88 tolend rigidity to the entire tow bar construction.

In use, the tow bar may be assembled and adjust'ed horizontally andvertically of the :towing vehicle and the vtowed vehicle in a mannerwhich -will be readily apparent to one skilled `in the zart.

The present tow bar construction also 4allows .for

shock absorption upon sudden stopping and starting of the towing vehiclein two directions. Should Athe towing vehicle stop suddenly, atheIinertia of the towed vehicle will vcause .the Vsliclable collar 88,because it carries the divergent bars 68 and 19, to -Jcompress the coilspring 199. Should the towing lvehicle start suddenly, the slidablecollar162 will move ina direction to the right of `the gures,compressing the coil spring 1B and also moving the cylinder 80 over thepiston l-rod v82 .for complete absorption of shock.

Having described the invention, whatis claimed as new is:

1. A tow 'bar comprising-a shaft, a ,plate horizontally fpivoted to oneend of ,said shaft, :means .for adjustably clamping said plate to thef-bumper of :a towing vehicle, a rst -collar .slidable on said shaftadjacent its pivoted end, resilient means urging said first collartowards lsaid ,pivotedfend Ielongated bars secured vat one of `theirAends to said first collar, 'means for `securing .the other ends of said.bars to `the bumper of -a towed vehicle in vertically 'adjustedposition, ia second collar slidable on said shaft adjacent `its freeend, means for vadjustaloly retaining the intermediate portions of saidbars on fsaid 'second collar, resilient means urging said second collartowards said free end of said shaft, and shockabsorbing means mounted onsaid shaft, said shock-absorbing means including a cylinder secured atone of its ends to said rst collar and a piston slidable in saidcylinder and adjustably secured at its outer end to .the free end ofsaid shaft.

2. The combination of claim '1 wherein rst- 'named clamping meansVincludes a substantially U-shaped member having a longitudinal slot in'its web, a pair of vertical spaced plates secured Ato the 'web '.011both sides of said slot, vertically spaced arcuate recesses in the freeedges of said plates, hooks extending through said slot havfing, arcuateybearings selectively received in said recesses, and means pivotallysecuring saidvertical plates to said rst-named plate.

3. The combination of claim 1 wherein said meansor adjustably retainingthe intermediate portions vof said bars on said second collar cludesopposing ears on said second collar, Vtur- Vther 'bars havinglongitudinally spaced :apertures and secured Yat one of their .ends uponsaid ears, rand bolts selectively received in said apertures andextending through the intermediate portions of said rst-named bars.

4. r'Ehe vcombination of yclaim 1 wherein .lastnamed resilient vmeansincludes an annular .ring secured centrally to said shaft and a .coilspring about said shaft between said .ring and said second colla-r.

`5,. The .combination of claim `1 wherein .said -iirst-named resilientmeans vincludes -an annular ring secured centrally to lsaid shaft and racoil spring about said shaft between said ring Yand said collar.

' JAMES O. HAM.

REFERENCES CITED 'The following references are .of record in ,the fileof this patent:

vUNITED 'STATES PATENTS Number Name Date 1,481,464 Morrison Mar. 18,-1'924 1,895,427 Sel'vester v Feb. "7, .1933 2,121,416 White ,June 21.,V1938 2,238,095 Alrncrantz Apr. l5, 19.41

